Many cell types are involved in the inflammatory process in rheumatic diseases. Understanding the biology of these diseases will require dissecting out the contribution of each of these cell subpopulations. The Cell Isolation and Phenotyping Core will provide technical expertise, assistance, and equipment of a reasonable cost to investigators in the research base whose studies require cell analysis. The Core will also provide training in the proper user and interpretation of flow cytometry. Expertise and assistance will be provided by core personnel in the following areas: Cell surface phenotype analysis Intracellular cytokine analysis Cell cycle analysis DNA index analysis Apoptosis analysis Gene expression analysis (green fluorescent protein, beta- galactosidase) Calcium flux analysis Cell sorting In addition, the Core will facilitate the acquisition, analysis, and storage of flow cytometry data, maintain standards and quality control for flow cytometry procedures, and assist in the development of new techniques as needed.